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Why Does My AC Smell Like Mildew?

Air conditioning should be refreshing and comforting. Nothing ruins the enjoyment of cool air quite like a mold or mildew smell coming with it. If your AC smells like mildew, body odor, decay, or other foul odors, it’s time to troubleshoot the problem and call a professional for effective cleaning and repairs.

Ready to contact a professional to take care of the problem? Call Dynamic Air Services at (949) 979-4409 for quick and reliable AC service in Orange County.

Read on for more information on mildew and mold in air conditioners.
What Does Mold Smell Like?
Mold and mildew grow best in dark and damp conditions. These conditions are common in air conditioner systems and provide the perfect breeding ground for mold. If you have never encountered mold before, you may not be sure what it even smells like.

Some describe mold as having an earthy or musty smell. Others compare it to old wet socks or rotten wood. A mildew smell is similar to the smell of mold. The smell might not be strong enough to discern. In this case, stand close to the vent with the strongest smell and breathe in. If the air feels humid or you start to sneeze, then there is most likely a mold problem.
Common Causes For Mildew Smell From Your AC
Mold and mildew smells can start at virtually any point in the flow of air conditioning. When working properly, AC units can overcome the presence of moisture, condensation, and exposure to the elements. Here are the most common reasons that a mildew smell begins to form:
  • Filter: If the filter is dirty and clogged or gets exposed to too much moisture, mildew can begin to grow. A lot of tiny organic particles get trapped in the filter, and moisture accelerates the mold growth. Remove the filter, clean around it, and replace it — up to once per month as necessary. Don’t forget to replace all of the filters in your home, not just one or two. This will prevent the spread of mold in the air conditioner.
  • Drip pan: Check to see if the drip pan under the AC unit has been knocked askew or is filling up too quickly. The drain may also be blocked up with dirt or leaves. The best way to empty a drip pan is to first turn off the air conditioner and then use a wet/dry vac to get rid of any standing water. You can likely correct small problems with the drip pan yourself, but if it seems difficult or the problem repeats — call a pro.
  • Condensate drain line: This line runs from the coils to the outside of the unit and removes the condensation created by the coils. To clean the condensate drain line, remove the cover of the pipe and pour a solution of one part water and one part vinegar into the pipe. After 30 minutes, rinse out the line with water. Check that the water is exiting through the exterior line. If it is not, there may be a clog within the line. Give an air conditioner technician a call if the problem seems too big to handle or if other issues arise.
  • Ductwork: Mildew can also form in the ducts and vents. There are a few reasons why your ductwork may have a mold issue. Oversized ducts cool rooms quickly, leading to excess moisture build up in the ductwork. Another reason why mold may be growing in your ducts is that there are leaks or tears. This can cause moisture to enter your ductwork and promote mold growth. An HVAC professional can thoroughly clean and seal the ductwork and locate the source of moisture.
  • Internal problems: The interior parts of the AC may be dirty and mildewy, possibly in addition to one of the above problems. This kind of internal mold growth may happen naturally through wear and tear, especially in older units. However, a newer unit that is developing internal mold problems may have an underlying issue. If the unit appears dirty or other measures do not fix the smell, an HVAC technician can provide a deep clean of the AC unit.
When to Call a Professional
If the mildew smell remains after you replace the filter and check the drain pan, call a professional. Depending on the location and extent of the mildew, cleaning an air conditioner can be quite difficult as a DIY project.

Mold tends to grow and spread quickly, so even if the problem began with the air filter or drain pan, your AC may continue to produce a mildew smell because of moisture and filth collected in the coils and/or ductwork.

Professional cleaning helps get rid of the smell faster and keeps the smell away longer. Simply cleaning, however, does not fix the root cause. If this is an ongoing issue, you have a problem with your air conditioning system that is causing this issue. Your technician can survey the situation to determine if an underlying problem needs to be fixed so the smell doesn’t keep coming back.
Preventing Mold in AC Unit
To prevent future mold growth in your air conditioner, follow these steps:
  • Replace filter and clean vents regularly.
  • Apply disinfectant and then an EPA-approved mold inhibitor to your heating and cooling systems.
  • Keep ducts dry by scheduling regular inspections.
  • Empty and clean drain pan and flush condensate lines frequently.
  • Schedule biannual HVAC maintenance and inspections.
Talk with your AC technician to find out how else you can prevent mildew in the AC unit.
Schedule AC Repair Service in Orange County Today
No one wants to deal with mold or mildew in their air conditioner. For help with a mildew or mold smell from the air conditioner in Southern California, call the experts at Dynamic Air Services to clean and fix the problem. We’ll have you smelling clean, healthy air as fast as possible.

Give our reliable team at Dynamic Air Services a call at (949) 979-4409 or contact us online.
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